Lighting systems, such as ceiling-, wall-, or surface-mounted lighting fixtures or luminaires, commonly illuminate spaces in which people live, work, or play. Despite an availability of a wide variety of commercial lighting fixtures, lighting designers often struggle with competing design objectives. A person occupying a work or living space may desire a fixture that is integrated esthetically and functionally with the environment. Meanwhile, an installer may prefer a fixture that offers easy access to light bulbs, wires, and adjustment mechanisms—items that often lack visual appeal. Addressing electrical safety, compliance with government and industry standards, energy efficiency, and heat dissipation adds to the difficulty of balancing design criteria. Moreover, many users prefer specific patterns and angles of illumination and would like a capability to adapt the lighting fixture or the luminaire according to their personal preferences.
The term “luminaire”, as used herein, generally refers to a system for producing, controlling, and/or distributing light for illumination. A luminaire can be a system that outputs or distributes light into an environment so that people can observe items in the environment. Such a system could be a complete lighting unit comprising one or more lamps; sockets for positioning and protecting lamps and for connecting lamps to a supply of electric power; optical elements for distributing light; and mechanical components for supporting or attaching the luminaire. Luminaires are also sometimes referred to as “lighting fixtures” or as “light fixtures.” A lighting fixture that has a socket for a bulb, but no inserted bulb, can still be considered a luminaire.
Conventional lighting technologies often fail to strike an adequate balance among competing functional, service, installation, aesthetic, safety, and regulatory objectives. For example, conventional ceiling-mounted fixtures often lack a capability to fit a wide range of ceiling types and thicknesses. This lack of flexibility can result in excessive installation costs associated with making shims or with modifying either a ceiling or a lighting fixture to achieve installation compatibility.
Another problem with conventional technology lies in aligning a new lighting fixture to an existing fixture, for example to create an array or a line of lights. Yet another problem concerns making optical adjustments to output a sought-after illumination pattern. One more problem relates to mating a conventional lighting fixture with a ceiling in order to provide, without undue labor expense, a clean and defect-free interface between the ceiling and the lighting fixture.
Accordingly, to address one or more of the aforementioned representative deficiencies in the art, an improved lighting fixture is needed. Moreover, a need exists for a lighting fixture that is readily adapted for mounting on a variety of surfaces, including ceilings that have different thicknesses. A need also exists for a lighting fixture that can be adjusted to provide geometric alignment with another fixture, lighting or otherwise. Yet another need is for a lighting fixture for which a person can readily control the pattern of illumination, including an angle of illumination or an optical axis. One more need is present for a lighting fixture that an installer can mate efficiently and cleanly with a hole in a ceiling or similar surface. A capability addressing one or more of these needs would decrease installation cost, offer better lighting, and/or provide a single fixture design that would serve multiple installation scenarios.